Synthetic polymer products have been widely used in commodities of life and various industrial fields such as construction, medical or agricultural fields, and are increasingly used for convenience and comfort of human life. PVC is a widely used all-purpose resin, has good weatherability, waterproof capability, chemical resistance, flame resistance, electrical insulation, is relatively low-priced, and moreover, its physical, chemical and electrical properties can be controlled by use of various additives to be designable for purposes, and thus is used for various applications, for example materials for packaging various products including clothes, storage containers, construction materials, toys or a sealant for preventing opening of medicines.
PVC has a limitation in molecular mobility due to its unique hierarchy structure and microcrystallite serving as physical crosslinks, and thus a low molecular weight liquid plasticizer is additionally used to manufacture PVC products, for example a phthalate plasticizer, a phosphate plasticizer, a trimellitate plasticizer, an epoxy plasticizer or an anti-chlorine plasticizer. However, it is reported that a phthalate plasticizer, the most widely used plasticizer migrates to the surface of products when being contacted with heat and a solvent, thereby causing damage to human health and the environment, and thus, advanced nations including South Korea regulate the phthalate plasticizer as an endocrine disruptor by law, and impose legal controls on its usage amount and extent of migration.
Therefore, efforts have been made to suppress migration of a plasticizer from PVC products.
For example, there have been attempts to replace a low molecular weight liquid plasticizer with a high molecular weight plasticizer. However, the high molecular weight plasticizer has disadvantages of reduced economical efficiency, insufficient plasticization and generation of chain entanglement.
Meanwhile, it has been reported that cyclodextrin forms a complex with a low molecular weight liquid plasticizer such as dioctyl phthalate (DOP), and thus contributes to suppress migration of the plasticizer from a flexible PVC, as disclosed in Journal of Applied Polymer Science, 1996, Vol. 59, P. 2089 “Effect of blending β-cyclodextrin with poly(vinyl chlorine) on the leaching of phthalate ester to hydrophilic medium”.
And, it has been reported that cyclodextrin has an inner cavity, in which lone pair exists with high density, and a phthalate plasticizer is bonded to the inner cavity with van der Waals forces, and thus migration of the plasticizer is suppressed, as disclosed in Chemical Reviews, 1998, Vo. 98, P. 1743 “Introduction and General Overview of Cyclodextrin Chemistry”, and hydroxyl functional groups of an outer part of cyclodextrin may be bonded to oxygen in ester of a phthalate plasticizer by a hydrogen bond, as disclosed in Industrial & Engineering Chemistry Research, 2003, Vol. 42, P. 949 “Water Solubility Enhancement of Phthalates by Cetyltrimethylammoniym Bromide and □Cyclodextrin”.
According to the above-mentioned papers, cyclodextrin of the following Chemistry Figure 2 is a cyclic compound, composed of a glucose group as a repeating unit in the same manner as α-cyclodextrin of the following Chemistry Figure 1, and has a hydrophilic outer part surrounded by hydroxyl functional groups and a hydrophobic inner cavity, and the inner cavity and the outer hydroxyl functional groups are physically and chemically bonded to a low molecular weight liquid plasticizer to form a complex, thereby suppressing migration of the plasticizer.

To apply such properties of cyclodextrin to PVC products, conventionally cyclodextrin particles were mechanically mixed with PVC and a low molecular weight liquid plasticizer in the manufacture of PVC products. However, a simple mechanical mixing method causes a cohesion phenomenon due to low dispersibility of cyclodextrin, and consequently reduces the performance of cyclodextrin for suppressing migration of the plasticizer and deteriorates a physical property of resultant PVC products. Further, the cohesion phenomenon causes a protrusion problem during an extrusion step in processing of the PVC products. To solve the problem, the above-mentioned papers suggested to dispersing PVC, DOP and cyclodextrin in a THF solvent and cast a resultant mixture. However, this has disadvantages of low economical efficiency, unrealizable mass-production of PVC products and incomplete solution of the cohesion problem of cyclodextrin.